CodeShare.io - Realtime code sharing for developers
Code2Flow - An easy solution to create product flows.
asciiflow - Infinite ASCII diagrams, save to Google Drive, resize, freeform draw, and export straight to text/html.
CodePile - A simple, free & rich collaborative code sharing experience
Flowchart.js - Draw SVG flow charts from simple text representations of the diagrams.
Marmoset - Create gorgeous code snapshots.